Method and apparatus for drum ring parting



June 22, 1965 F- KuTA 3,190,094

METHOD AND APPARATUS FOR DRUM RING PARTING Filed Dec. 3, 1962 2 Sheets-Sheet 1 W FIG. I

' ,/32 I M v FRANK JZ U i- 3 's [I M M Mew ATTORNEYS June 22, 1965 I KuTAs 3,190,094

METHOD AND APPARATUS FOR DRUM RING PARTING Filed Dec. 5, 1962 V 2 Sheets-Sheet 2 FIG. 3 t

INV TOR.

ANK J. lav-As FIG. 4 FR ATTORNE Y5 United States Pat n This invention relatesto automotive brake drums and in particular to the method and the apparatus by which a double brake drum which has been cast as a unit can be 7 parted into two conventional brake drums.

In a conventional method of manufacturing brake drums, a strip of low carbon steel isformed into a loop and its ends are butt welded to form a hoop. The welded area is then trimmed so that the hoophas a uniform cross section. Because two drums are to be cast as a unit, the hoop is formed into a drum band having a contour of two drums with their open ends abutting. The end edges of the drum band extend radially inward to serve as a mold for subsequent casting of an inner lining'as'well as to provide a flangeto which a drum back is later attached. The contoured band is fluxed, preheated, placed in a chuck and rotated about'its longitudinal axis While molten cast iron is poured into the rotating band where centrifugal force holds it in place until it solidifies. A metallurgical bond is formed between the cast iron lining and'the steel band which reinforces the cast iron lining. After cooling; the'double drum is parted to form two single drums which are then rough machined. A drum back can then be attached to the flange and the remaining finish operations performed. i

This invention relates to parting a double brake drum into two single drums. Therusual practice is'to cut the double drum in half by a machining operation. However, a machining operation has two principal drawbacks; first, parting tool attrition is high due to slag and chilled iron near the inner surface of the cast iron lining and, second,

an extra width or patting allowance has to be provided adjacent the partingline' to compensate for material removed during the machining operation. On double drums for ordinary passenger cars, a parting allowance of approximately one-quarter inch is usually provided for parting operations previously used. v i a This invention contemplates a method and an apparatus for parting double drums that decrease parting tool wear, resharpeningand replacement; that decrease the parting allowance necessary in the prior art thereby redncing ma terial. costs; that eliminate expenses involved in handling machine chips; that reduce finish andcleanup machining; and that produce. a parting operation that is faster than the parting operation previously used. 1

' In the drawings: 1 f

FIG. 1 is a view partly in section showing the details of the upper and lower parting tools for parting double dI'llHlS. Z V I r 1 1 FIG. 2 is a schematic View showing the parting tools of FIG. 1 operated in an upright machine.

FIG. 3 illustrates the approximate position of the parting tools just'prior to separation of the double drum;

FIG. 4 is an enlarged fragmentary view of a .single drum illustrating the displacement of metal by theparting operation; 7 a r The double brake drum 16 that isto be parted comprises a contoured outer drum band 18 made of lowcarbon steel and a lining 20 centrifugally cast of-iron. Band 18 has radially inward extending flanges 19. The-machine (FIG. 2) for parting the double drum 16 generally comprises an upright frame 21, ,a vertically fixed upper rotary parting tool assembly 22,.a vertically movable lower rotary parting tool assembly 24, a motor 25 and 2 gear train 26 for rotating upper parting tool assembly 22, a motor 27 and gear train 28 for rotating lower parting tool assembly 24, and an air cylinder 39 for moving lower parting tool assembly 24 vertically. Frame 21 has a base 31, a pair of spaced uprights 32, 34 and an upper cross piece 36. Uprights 32, 34 have vertically extending ways 38, 49 shown in dotted lines, in which a pair of upper bearing supports 42 are'fixed-ly mounted and a pair of lower bearing supports 44 are mounted for vertical movement therein. Upper parting tool assembly 22 has an arbor 46 journalled in upper bearing supports 42 by bearings 48 (FIG. 1). Lower parting tool assembly 24 has an arbor 5t) journalled in lower bearing supports 44 by bearings 52 (FIG, 1). A platen 62 mounts bearing supports 44 and motor 27 for vertical movement by air cylinder 39. Separate switches (not shown) energize motors 25,27; Preferably the switch for motor 27 is positioned adjacent way 38 and actuated by the upward travel of bearing supports 44. V

As particularly shown in FIG. l,.double drum 16 is supported eccentrically on a lower parting tool assembly 24. Parting tool assembly 24 comprises a centrally disposed annular parting tool 64 flanked by wheels 66 which are in'turn flanked by retaining rings 68, all of'which are keyed on arbor 59. Parting tool 64 has a relatively blunt, wedge-shaped cross section. Preferably the included angle 7 ti between the faces of parting tool 64 is 80 (eighty) degrees. Wheels 66 have rubber tires 72 bonded thereto. The diameter through wheels 66 and tires 72 is somewhat smaller than the diameter of the openings bordered by flanges19 so that drum 16 can be positioned on lower parting tool assembly 24. Rubber tires 72 extend radially beyond the tip of parting tool 64 as shown in FIG. 1. Retaining rings 68 have a radial dimension slightly less than the radial dimension of parting tool 64 and are adapted to fit inside flanges 1'9 with minimum axial clearance to center doubledrum 16 with respect to parting tool 64. A pair of guides '76, 78 are also keyed to arbor 59 on' opposite sides of rings 68 and spaced therefrom by spacers 74. Guide 78 comprises a pair of rings and a spacer to provide'an annular slot 80. Guides 76, 78 en- L gage flanges19 of double drum 16 to retain the drum halves on lower assembly 24 after the parting operation. Arbor has an integral flange 79. The elements of lower parting too-l assembly 24 that arekeyed to arbor 50 are retained. axially thereon bet-ween flange "79 and a lock nut 31 threaded onthe outer end of arbor 5t).

Upper parting tool assembly 22 comprises an annular parting tool 82 keyed on arbor 46 and held in place by spacer-retainer rings 84, 86 also keyed on arbor 46. An

annular guide 88 is keyed on arbor 46 between ring 84 and a further spacer-retainer ring 87. Annular guide 88 is vertically aligned with slot 8%. in guide 78 onlower parting tool assembly 24. The keyed elements are retained on. arbor 46 by a lock nut 89. Upper parting tool 82 may be of slightly larger diameter than lower parting tool 64, but has a similar relatively blunt, wedge-shaped cross section and is vertically aligned with parting tool 64. Gear trains 2.6, 28 are chosen so that the outer pe ripheral tips ofparting tools 32, 64 are driven in opposite rotational directions at the same peripheral speed.

The parting operation is as follows. Drum 116 is positioned onto lower parting tool assembly 24 and supported eccentrically thereto by rubber tires 72 which space the radially inner surface of lining 20 from the tip of wedgeshaped parting tool 64 (FIG. 1, full lines). Retaining rings 68 coactwith flanges-19 to center doublerdrum 16 withrrespec-t to parting tool 64. Motor 25 is energized to rotate parting tool 82. Air. cylinder 30 is then actuated toraise platen 62, bearing supports 44, lower par-ting tool assembly 24, motor 27 and gear train 28, upper parting tool 82 being aligned with lower parting tool 64 along Patented June. 22, 1965 occurs.

outer band 18' is completely severed and inner lining 20' For a double drum used on it about its axi-s. As lowerparting tool, assembly 24 moves further upward, parting tool 82 engages drumlfi asshown in broken-lines in FIG. .1 and then rubber tires 72 are compressed until loWerpar-ting tool 64 engages the inner rotary partingtool having a wedge-shaped cross section, '10

surface of lining ZiL sandWiching double drumv 16 between rotating parting tools64, 82. Cont-inuedrnovement of parting tools 64, 82 toward each other simultaneously applies localized radial pressure to the drum and rolls V-shaped grooves into east lining 20 and the outer drum 18 at the proposed line'of parting. Continuedapplication of localizedradial pressure completely severs outer band 18 and grooves the inner and outer surfaces of lining 20. Grooving as used in this application to describe the penetration of parting tools 64 and r p 82 into the lining 20 andouter drum band 18 includes,

but is not, limited to scoring, shearing, and deforming. FIG. 3 shows the assembly just before total separation At this point rubber tires 72 are compressed,

is grooved on.both sides.

iron lining comprising a frame, a rotary parting tool assembly rotatably supported on said frame, said assembly comprising meansfor yielclably supporting a doublebrake drumon said assemblyfor co-rotation therewithand an annular parting] tool having a Wedge -shapedcross sec-1 'tion, said parting tool, being adapted to engage the lining of said double brake drum at the proposedline of parting when said drum is supported on said assembly, .a second said second rotary parting toolbeing rotatably supported on said frame in alignment with said first partingtool and, adapted to engage the outer band of said double brake drum when said drum is supported on said pa'rting; tool 1 assembly, means for rotating saidparting tools and means lining bonded to said band, the ends of said band having radially inward extending annular flangesgsaid apparatus ordinary passenger cars, when upper and lower parting tools 82, 64 have each penetrated cast iron lining-20 to a depth of about-three sixty-fourths of an'inch from opposite sides thereof, sufi'icient localized stresses are set 'up along the proposed line of parting to part lining 20. Suitable stops (not shown) 'may, be'provided, jas. for example in ways 38,40, to prevent clashing of parting j tools 64, 82 after the double drum is completely severed. Annular guide 88 rides into slot 80 to assure vertical alignment of parting tools 82, 64, as the tools are brought together.

FIG. 4 shows a fragment of a single drum 99 after the parting operation. Since the parting operation is by mug 7 Guides 76, 78 'keep the separated halves of double, drum 16 positioned on lower parting tool assernbly 24. r

for moving said parting tools toward'each other to engage said drum. f

4. An apparatus for parting 'a double brake drumhav ing an outer contoured steel band and an inner castiron comprising a frame, a:rotary parting tool assembly CHI? ried by'said frame and adapted to support said drum for v co-rotation therewith, said j parting tool assembly cornprising a centrally, positioned, annular. parting tool adapted to engage the inner-surface of saididrum. at the I proposed line of parting, said parting tool having a blunt, i

wedge-shaped cross sectionja pair of'yieldable annular members located at either side .of said partingtool and extending radially outward past-the radially outerportion of said parting tool to support'said drum .on said rotary partingtool assembly, a pair of-retaining ringspositioned adjacent said yield-able members remote from said parting tool and adapted to engagesaid flanges to centerlsaid i drum with respect to said parting tool, saidreta'ining rings having a slightly lesser radial extent than said part! ing tool, a second rotary parting tool having its axis of rotation parallelto the, rotational axis of said parting tool assembly, said secondjrotary parting tool having a 1 blunt, wedge-shaped cross section and being adapted to ing rather than machining, the localized radial pressure of parting tools 64, 82 forms the V-shaped groove 92 in steel band 18 by deforming or flowing-the metal at the proposed line of parting as indicatedby the'small burr or projection 94 in FIG. 4. Only minimum cleanup' machining is required 'at the drum was parted.

Because metal is not machined away from hand 18 and, addition-ally, because tools 64, 82 do not penetrate the open ends where the double entire thickness of lining 20, the finish parting allowance is reduced to approximately one thirty-second of aninch for the open end of each single drum, a total 'of' onesix-teenth of an inch or less of the double drum, whereas drum with said lining secured to said band by a metala total allowance of one-quarter of an inch was usually,

provided for parting operations previously used. I

Iclaim: i

1. An apparatus. for parting a double brake drum having an outer contoured steel band and an inner cast iron lining comprising opposed rotary parting tools havingia space theretbetween, each of, said par-ting toolshaving-a' blunt, wedge-shaped cross section, means for rotatably supporting adoublebrake drum in the space between said parting tools, said parting tools being adapted to engage opposite sides. of said double drum at the proposed line of parting when said double drum is supported in'the space between said parting tools, and means for moving said parting tools into engagement with said drum at the proposed line of parting.

2. The apparatus set forth in claim 1 wherein said wedge-shaped cross section is formed by faces having an includedangle in the order of eighty degrees.

3. An apparatus for parting a double brake drum having an outer con-toured steel bandwand an inner cast engage the outer surface of said d-rumat said proposed line of parting, means for causing relative movement of said wedge-shaped tools perpendicular to their rota tional axes into engagementwith said drum, and means for rotating said partingtools.

5. The apparatus set forth in claim yieldable in a radial direction.

6. In the method ofmakingbrake drums, whereinl a lining of iron is cast intoa steel drum band having {a contour of two single drums with their open ends'joined.

at a proposed line of' parting to form a double ,brake' lurgical bond, the step of parting said double drum to form two single brake drums by applying with a toolza localized radially outward pressure to the inner surface of said lining at said proposed line of parting while si-.

multaneously applying-with a tool a localized radially inward pressure to the outer surface of said band .atsaid proposed line of parting to sever said band' and groove said lining at opposite'surfaces thereof until said lining separates along said proposed line of parting. 7. 1n the method of making brake drums wherein a lining of iron is centrifugally cast into a steel drum band" having a contour of. two single drums with their open ends joined at a proposed .line of parting to form a double brake drum with saidlining secured to saidband by a metallurgical bond, the step of panting said double drum to form two single drums by continuously rolling a circumferentiaLV-shaped groove progressivelydeeper intoj the inner surface of said liningat said proposed line of parting while simultaneously .andcontiuuously rolling a similar V-shaped groove progressively deeper into the outer surface of said band toward the center of said 3 whereinsaid; means foryieldably supporting said drumpcomprises a ring which extends radially outwardbeyond said annular parting tool on said first assembly, said ring being double drum at said proposed line of parting until said band separates along said proposed line of parting and said lining is grooved at the inner and outer surfaces thereof until the double drum parts at said proposed line of parting. p

8. In the method of making brake drums wherein a lining of iron is cast into a steel drum band having a contour of two single drums with their open ends joined at a proposed line of parting to form a double brake drum with said lining secured to said band by a metallurgical bond, the step of parting said double drum to form two single drums by engaging the outer surface of said band at said proposed line of parting with a wedgeshaped rotary parting tool, engaging the inner surface of said oast lining at said proposed line of parting with a similar wedge-shaped rotary parting tool, and rotating said wedge-shaped tools and said drum while simult-aue ouslyr causing relative movement of said parting tools toward each other into engagement with the double drum to flow the material of said band at said proposed line of parting until said band separates at said proposed line of parting and to groove said lining at opposite surfaces thereof until said lining separates. V

9. The method set forth in claim 8 further comprising the step of yieldably supporting said double drum for movement in a direction radiallyof said double drum and relative to said similar parting tool'when said drum and said parting tools are rotating and said parting tools are moved relative to each other into engagement with said double drum.

'seierences Cited bythe Examiner UNITED STATES PATENTS V V V 8/77 Atkinson 2252 ANDREW R. IUHASZ, Primary Examiner. 

6. IN THE METHOD OF MAKING BRAKE DRUMS WHEREIN A LINING OF IRON IS CAST INTO A STEEL DRUM BAND HAVING A CONTOUR OF TWO SINGLE DRUMS WITH THEIR OPEN ENDS JOINED AT A PROPOSED LINE OF PARTING TO FORM A DOUBLE BRAKE DRUM WITH SAID LINING SECURED TO SAID BAND BY A METALLURGICAL BOND, THE STEP OF PARTING SAID DOUBLE DRUM TO FORM TWO SINGLE BRAKE DRUMS BY APPLYING WITH A TOOL A LOCALIZED RADIALLY OUTWARD PRESSURE TO THE INNER SURFACE OF SAID LINING AT SAID PROPOSED LINE OF PARTING WHILE SIMULTANEOUSLY APPLYING WITH A TOOL A LOCALIZED RADIALLY INWARD PRESSURE TO THE OUTER SURFACE OF SAID BAND AT SAID PROPOSED LINE OF PARTING TO SEVER SAID BAND AND GROOVE SAID LINING AT OPPOSITE SURFACES THEREOF UNTIL SAID LINING SEPARATES ALONG SAID PROPOSED LINE OF PARTING. 